Display device

ABSTRACT

A display device according to one aspect of the present invention includes a first substrate including a pixel portion and a terminal portion, a second substrate arranged to face the pixel portion, a first light source device arranged in the terminal portion, and irradiating a first end surface of the second substrate with first light, a liquid crystal layer arranged between the first substrate and the second substrate, and a semiconductor element arranged on a side opposite to a side of the pixel portion across the first light source device, and electrically coupled with the terminal portion, wherein the first light is propagated while reflected between the first substrate and the second substrate, and the liquid crystal layer modulates the propagated first light.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from Japanese Application No.2016-051426, filed on Mar. 15, 2016, and Japanese Application No.2017-032338, filed on Feb. 23, 2017, the contents of which areincorporated by reference herein in its entirety.

BACKGROUND 1. Technical Field

The present disclosure relates to a display device.

2. Description of the Related Art

As edge light display devices, display devices described in JapanesePatent No. 3697925, Japanese Patent Application Laid-open PublicationNo. 2004-309774, Japanese Patent Application Laid-open Publication No.2012-150946 (JP-A-2012-150946), and Japanese Patent ApplicationLaid-open Publication No. 2012-185934 (JP-A-2012-185934) are known. Inthese display devices, a light source device is arranged in an endportion of a light-guiding plate, and light radiated from the lightsource device is propagated inside the light-guiding plate and isexpanded in a plane manner. To increase brightness of display, the lightsource devices are provided to a plurality of sides of the light-guidingplate (see JP-A-2012-150946 and JP-A-2012-185934).

If a semiconductor element such as an IC chip exists near the lightsource devices, the semiconductor element may malfunction due to stronglight from the light source devices. Therefore, the light source deviceis favorably not arranged in a terminal portion where the semiconductorelement is arranged. However, this configuration significantly limitsarrangement of the light source devices.

SUMMARY

A display device according to one aspect of the present inventionincludes a first substrate including a pixel portion and a terminalportion, a second substrate arranged to face the pixel portion, a firstlight source device arranged in the terminal portion, and irradiating afirst end surface of the second substrate with first light, a liquidcrystal layer arranged between the first substrate and the secondsubstrate, and a semiconductor element arranged on a side opposite to aside of the pixel portion across the first light source device, andelectrically coupled with the terminal portion, wherein the first lightis propagated while reflected between the first substrate and the secondsubstrate, and the liquid crystal layer modulates the propagated firstlight.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view of a display device according to a firstembodiment;

FIG. 2 is a sectional view along a C1-C2 line of FIG. 1;

FIG. 3 is a diagram illustrating an enlarged configuration of a vicinityof a terminal portion of FIG. 2;

FIG. 4 is a sectional view illustrating a configuration of a liquidcrystal layer;

FIG. 5 is a sectional view illustrating the liquid crystal layer in anon-scattering state;

FIG. 6 is a sectional view of the liquid crystal layer in a scatteringstate;

FIG. 7 is a diagram for describing behavior of incident light in a casewhere there is a gap between a light source device and a light incidentsurface;

FIG. 8 is a diagram for describing behavior of incident light in a casewhere there is no gap between the light source device and the lightincident surface;

FIG. 9 is a sectional view of a display device according to a secondembodiment;

FIG. 10 is a plan view of a display device according to a thirdembodiment;

FIG. 11 is a sectional view of a display device according to a fourthembodiment;

FIG. 12 is a sectional view of a display device according to a fifthembodiment;

FIG. 13 is a sectional view illustrating a variation of arrangement of alight source device;

FIG. 14 is a plan view of a display device according to a seventhembodiment;

FIG. 15 is a plan view of a display device according to an eighthembodiment;

FIG. 16 is a sectional view of a display device according to a ninthembodiment;

FIG. 17 is a sectional view illustrating a configuration of a lightsource;

FIG. 18 is a schematic view of a passive matrix panel;

FIG. 19 is an equivalent circuit diagram of the passive matrix panel;

FIG. 20 is a schematic view of an active matrix panel; and

FIG. 21 is an equivalent circuit diagram of the active matrix panel.

DETAILED DESCRIPTION

Forms for implementing the invention (embodiments) will be described indetail with reference to the drawings. The present invention is notlimited by content described in the embodiments below. Configurationelements described below include elements easily conceived by a personskilled in the art and elements substantially the same. Further, theconfiguration elements described below can be appropriately combined.The disclosure is merely an example, and appropriate modifications whichmaintain the points of the invention, and which can be easily arrived atby a person skilled in the art, are obviously included in the scope ofthe present invention. To make description more clear, the drawings maybe schematically illustrated in the width, thickness, shape, and thelike of respective portions, compared with actual forms. However, suchillustration is merely an example, does not limit the construction ofthe present invention. In the present specification and drawings,elements similar to those described with respect to the drawings thathave already been mentioned are denoted with the same reference signs,and detailed description may be appropriately omitted.

First Embodiment

FIG. 1 is a plan view of a display device 100 according to a firstembodiment. FIG. 2 is a sectional view along a C1-C2 line of FIG. 1.FIG. 3 is a diagram illustrating an enlarged configuration of a vicinityof a terminal portion of FIG. 2.

As illustrated in FIGS. 1 and 2, the display device 100 includes adisplay panel 1, a plurality of light source devices 40, a plurality ofsemiconductor elements 50, and a plurality of flexible printed circuitsubstrates (hereinafter, referred to as “FPCs”) 60.

The display panel 1 includes a first substrate 10, a second substrate20, and a liquid crystal layer 30 (see FIG. 3). The first substrate 10includes a pixel portion 11 and a terminal portion 12. The pixel portion11 has, for example, a square shape. The terminal portion 12 includes,for example, a first terminal portion 12 a along a first side 11 a ofthe pixel portion 11, and a second terminal portion 12 b along a thirdside 11 c adjacent to the first side 11 a. The second substrate 20 isarranged to face the pixel portion 11. The second substrate 20 issmaller than the first substrate 10. The terminal portion 12 projectsoutside the second substrate 20.

The display panel 1 may be a passive matrix panel not including aswitching element, or may be an active matrix panel including theswitching element.

As illustrated in FIGS. 18 and 19, a passive matrix panel PMLCD includeselectrodes (first electrodes E1 and second electrodes E2) extending in alongitudinal direction and a cross direction in plan view, and wiringsLW electrically coupled to the electrodes. The electrodes are, forexample, transparent electrodes, and are arranged to face each otheracross the liquid crystal layer 30.

A plurality of the first electrodes E1 are supplied with drive signalsby a first driver D1 in order of E1X₁, E1X₂, E1X₃, E1X₄, E1X₅, . . .E1X_(m), for example. A plurality of the second electrodes E2 aresupplied with drive signals by a second driver D2 in order of E2Y₁,E2Y₂, E2Y₃, E2Y₄, E2Y₅, . . . E2Y_(n). A region where the liquid crystallayer 30 is driven by one first electrode and one second electrode isone sub-pixel. A plurality of the sub-pixels arranged in a matrix mannerform the pixel portion 11.

As illustrated in FIGS. 20 and 21, in a case where the display panel 1is an active matrix panel AMLCD, the display panel 1 includes data linesDL and gate lines GL extending in a longitudinal direction and a crossdirection in plan view, and switching elements Tr in intersectionportions of the data lines DL and the gate lines GL.

Pixel electrodes E3 are respectively coupled to the switching elementsTr. The first substrate 10 is provided with a plurality of the pixelelectrodes E3 in a matrix manner. The plurality of gate lines GL aresupplied with gate signals by a third driver D3 in order of GL1, GL2,GL3, GL4, GL5, . . . GLm, for example. The plurality of data lines DLare supplied with image signals by a fourth driver D4 in order of DL1,DL2, DL3, DL4, DL5, . . . DLn, for example.

The second substrate 20 is provided with a common electrode E4 common tothe pixel electrodes E3. The image signal (drive voltage) supplied tothe pixel electrode E3 through the switching element Tr is held in acapacitive element CL formed of the pixel electrode E3 and the commonelectrode E4. A region where the liquid crystal layer 30 is driven byeach of the pixel electrodes E3 and the common electrode E4 is onesub-pixel. A plurality of the sub-pixels arranged in a matrix mannerform the pixel portion 11.

As the switching element, a thin film transistor may be used. Examplesof the thin film transistor include a bottom gate transistor and a topgate transistor. Further, for a semiconductor layer of the thin filmtransistor, amorphous silicon, polycrystal silicon, or an oxidesemiconductor may be used. In the present embodiment, the active matrixpanel AMLCD is used as the display panel 1, and a thin film transistorusing amorphous silicon is used as the thin film transistor, forexample.

In the terminal portion 12, the wirings from the pixel portion 11 andthe plurality of semiconductor elements 50 are electrically coupled. Inthe present embodiment, for example, as the plurality of semiconductorelements 50, a plurality of first semiconductor elements 51 electricallycoupled with the first terminal portion 12 a, and a plurality of secondsemiconductor elements 52 electrically coupled with the second terminalportion 12 b are provided. The first semiconductor element 51 is, forexample, a semiconductor element electrically coupled with the dataline. The second semiconductor element 52 is, for example, asemiconductor element electrically coupled with the gate line. Theplurality of semiconductor elements 50 are mounted on the terminalportion 12 by a chip on glass (COG) method, for example. The pluralityof FPCs 60 corresponding to the semiconductor elements 50 areelectrically coupled to the terminal portion 12. The semiconductorelement 50 is electrically coupled with an external device through thecorresponding FPC 60.

Note that the wirings from the pixel portion 11 refer to one or both ofelectrodes and wirings extending in the longitudinal direction and thecross direction in plan view in a case where the display panel 1 is thepassive matrix panel. Further, the wirings from the pixel portion 11refer to one or both of gate lines and data lines in a case where thedisplay panel 1 is the active matrix panel. The gate line and the dataline may be electrically coupled with one semiconductor element.

The plurality of light source devices 40 are provided around the pixelportion 11. The light source device 40 irradiates the pixel portion 11with light L. In the present embodiment, for example, as the pluralityof light source devices 40, a first light source device 41, a secondlight source device 42, a third light source device 43, and a fourthlight source device 44 are provided. The first light source device 41 isarranged in the first terminal portion 12 a. The second light sourcedevice 42 is arranged in a position facing the first light source device41 across the pixel portion 11. The third light source device 43 isarranged in the second terminal portion 12 b. The fourth light sourcedevice 44 is arranged in a position facing the third light source device43 across the pixel portion 11.

The first light source device 41 is arranged along the first side 11 aof the pixel portion 11, and irradiates a first end surface 21 of thesecond substrate 20 with first light L1. The second light source device42 is arranged along the second side 11 b of the pixel portion 11, andirradiates a second end surface 22 of the second substrate 20 withsecond light L2. The third light source device 43 is arranged along athird side 11 c of the pixel portion 11, and irradiates a third endsurface 23 of the second substrate 20 with third light L3. The fourthlight source device 44 is arranged along a fourth side 11 d of the pixelportion 11, and irradiates a fourth end surface 24 of the secondsubstrate 20 with fourth light L4.

As illustrated in FIG. 3, the light source device 40 includes an FPC 45adhering to the terminal portion 12, and a plurality of light sources 46mounted on the FPC 45. The plurality of light sources 46 are arrangedalong an outer periphery of the pixel portion 11. As the light source46, a light emitting diode is used, for example. The light source device40 is arranged to face the end surface of the second substrate 20 in astate where a light irradiation surface 40 a faces the end surface ofthe second substrate 20. The end surface of the second substrate 20, theend surface facing the light irradiation surface 40 a, is a lightincident surface SE that the light L enters. A gap is provided betweenthe light irradiation surface 40 a and the light incident surface SE.The gap is an air layer G. The light L radiated from the light sourcedevice 40 is propagated in a direction away from the light incidentsurface SE while reflected at an outer surface 10A (a surface on anopposite side of the liquid crystal layer 30 side) of the firstsubstrate 10 and an outer surface 20A of the second substrate 20.

As illustrated in FIG. 1, the first semiconductor element 51 is arrangedon an opposite side of the pixel portion 11 side across the first lightsource device 41. The first light L1 is radiated only on the pixelportion 11 side, and is not radiated on the first semiconductor element51 side. Therefore, the first semiconductor element 51 is less likely tomalfunction by the first light L1. Similarly, the second semiconductorelement 52 is arranged on an opposite side of the pixel portion 11 sideacross the third light source device 43. The third light L3 is radiatedonly on the pixel portion 11 side, and is not radiated on the secondsemiconductor element 52 side. Therefore, the second semiconductorelement 52 is less likely to malfunction by the third light L3.

As illustrated in FIG. 3, a resin 55 having low thermal conductivity isprovided between the first semiconductor element 51 and the first lightsource device 41. The thermal conductivity of the resin 55 is smallerthan that of the air. A side surface of the first semiconductor element51 on the first light source device 41 side is favorably coated with theresin 55 having low thermal conductivity. The resin 55 having lowthermal conductivity can prevent conduction of heat from the first lightsource device 41 to the first semiconductor element 51. Therefore, thefirst semiconductor element 51 is less likely to be deteriorated by theheat from the first light source device 41.

Although illustration is omitted, a resin having low thermalconductivity is also provided between the second semiconductor element52 and the third light source device 43. The resin 55 having low thermalconductivity can prevent conduction of heat from the third light sourcedevice 43 to the second semiconductor element 52. Therefore, the secondsemiconductor element 52 is less likely to be deteriorated by the heatfrom the third light source device 43. Note that examples of the resin55 having low thermal conductivity include a silicone resin, an epoxyresin, and a UV polymerized resin.

As illustrated in FIGS. 2 and 3, the liquid crystal layer 30 is arrangedbetween the first substrate 10 and the second substrate 20. The liquidcrystal layer 30 modulates the light L propagated while reflectedbetween the first substrate 10 and the second substrate 20. A sealmaterial 39 that seals the liquid crystal layer 30 is provided betweenthe first substrate 10 and the second substrate 20. The seal material 39is provided along the outer periphery of the pixel portion 11 in a framemanner. A plurality of pixels PX are arranged in the pixel portion 11 ina matrix manner. A pixel electrode 13 is provided in each of the pixelsPX on the first substrate 10. The plurality of pixels PX may beelectrically coupled with the terminal portion 12 through a plurality ofrouting wirings (not illustrated). The second substrate 20 is providedwith a common electrode 14 common to the pixels PX.

An example of the display panel 1 being the passive matrix panelincludes a case in which the pixel electrodes 13 and the commonelectrodes 14 are formed into a strip form, and the pixel electrodes 13and the common electrodes 14 extend in a longitudinal direction and in across direction in plan view, respectively. The pixel electrodes 13 andthe common electrodes 14 are coupled with wirings, respectively, and areelectrically coupled with the semiconductor element. An example of thedisplay panel 1 being the active matrix panel includes a case in whichthe switching element, for example, the thin film transistor iselectrically coupled with the pixel electrode 13. The gate lines and thedata lines are electrically coupled with the semiconductor element.

FIG. 4 is a sectional view illustrating a configuration of the liquidcrystal layer 30. FIG. 5 is a sectional view illustrating the liquidcrystal layer 30 in a non-scattering state. FIG. 6 is a sectional viewillustrating the liquid crystal layer 30 in a scattering state.

As illustrated in FIG. 4, the liquid crystal layer 30 includes a bulk 31formed of a polymer and a plurality of fine particles 32 dispersed inthe bulk 31. The fine particles 32 are formed of liquid crystal. Thebulk 31 and the fine particles 32 have optical anisotropy.

The liquid crystal layer 30 is formed by the following method, forexample. First, a solution in which liquid crystal is dispersed in amonomer for the polymer is filled between the first substrate 10 and thesecond substrate 20. The first substrate 10 includes a first basematerial 19, and the pixel electrodes 13 and a first orientation film 61provided on the first base material 19. The second substrate 20 includesa second base material 29, and the common electrode 14 and a secondorientation film 62 provided on the second base material 29. The firstorientation film 61 and the second orientation film 62 are, for example,vertical orientation films.

Next, the monomer is polymerized by ultraviolet rays or heat to form thebulk 31 in a state where the monomer and the liquid crystal areorientated by the first orientation film 61 and the second orientationfilm 62. Accordingly, the reverse mode liquid crystal layer 30 isformed, in which the liquid crystal is dispersed in gaps of a polymernetwork formed in a mesh manner.

The orientation of the liquid crystal included in the fine particles 32is controlled by the voltage applied between the pixel electrode 13 andthe common electrode 14. With change of the orientation of the liquidcrystal, the degree of scattering of the light L is changed. The liquidcrystal layer 30 modulates the light L by changing the degree ofscattering of the light L. The brightness of the light L radiated fromthe display panel 1 to an outside is changed according to the degree ofscattering of the light L.

For example, as illustrated in FIG. 5, the direction of an optical axisAx1 of the bulk 31 and the direction of an optical axis Ax2 of the fineparticle 32 are equal to each other in a state where no voltage isapplied between the pixel electrode 13 and the common electrode 14. Theoptical axis Ax2 of the fine particle 32 is parallel to thelayer-thickness direction of the liquid crystal layer 30. The opticalaxis Ax1 of the bulk 31 is parallel to the layer-thickness direction ofthe liquid crystal layer 30 regardless of existence/non-existence of thevoltage.

The ordinary ray refractive index of the bulk 31 and the ordinary rayrefractive index of the fine particle 32 are equal to each other. Theextraordinary ray refractive index of the bulk 31 and the extraordinaryray refractive index of the fine particle 32 are equal to each other. Inthe state where no voltage is applied between the pixel electrode 13 andthe common electrode 14, a difference in the refractive index betweenthe bulk 31 and the fine particle 32 becomes zero in every direction.The liquid crystal layer 30 is in the non-scattering state where theliquid crystal layer 30 does not scatter the light L. The light L ispropagated in the direction away from the light source device 40 whilebeing reflected between the first substrate 10 and the second substrate20.

As illustrated in FIG. 6, in a state where the voltage is appliedbetween the pixel electrode 13 and the common electrode 14, the opticalaxis Ax2 of the fine particle 32 is inclined by an electric fieldoccurring between the pixel electrode 13 and the common electrode 14.Since the optical axis Ax1 of the bulk 31 is not changed by the electricfield, the direction of the optical axis Ax1 of the bulk 31 and thedirection of the optical axis Ax2 of the fine particle 32 are differentfrom each other. The liquid crystal layer 30 is the scattering statewhere the liquid crystal layer 30 scatters the light L. The light L ispropagated while being reflected between the first substrate 10 and thesecond substrate 20, and is scattered in the pixel PX in the scatteringstate. The scattered light L is radiated to an outside of the displaypanel 1, and is observed as image light.

An example in which the first orientation film 61 and the secondorientation film 62 are vertical orientation films has been described.However, the first orientation film 61 and the second orientation film62 may be horizontal orientation films. The first orientation film 61and the second orientation film 62 may be anything as long as they havea function to orientate the monomer in a predetermined direction inpolymerizing the monomer. By this function, the monomer becomes apolymerized polymer in a state of being orientated in the predetermineddirection. In a case where the first orientation film 61 and the secondorientation film 62 are the horizontal orientation films, the directionof the optical axis Ax1 of the bulk 31 and the direction of the opticalaxis Ax2 of the fine particle 32 are equal to each other and become adirection perpendicular to a film thickness direction in the state whereno voltage is applied between the pixel electrode 13 and the commonelectrode 14. The direction perpendicular to the film thicknessdirection corresponds to a direction along a side of the first substrate10 in a plan view.

In the display device 100 of the above-described present embodiment, thefirst light L1 from the first light source device 41 does not directlyenter the first semiconductor element 51. Further, the third light L3from the third light source device 43 does not directly enter the secondsemiconductor element 52. Therefore, the first light source device 41and the third light source device 43 can be arranged in the terminalportion 12 while suppressing malfunction of the first semiconductorelement 51 and the second semiconductor element 52. According to thisconfiguration, the positions of the light source devices 40 are notlimited by the position of the terminal portion 12, and thus the degreeof freedom of arrangement of the light source devices 40 is high.Therefore, for example, the plurality of light source devices 40 can besymmetrically arranged around the pixel portion 11. In thisconfiguration, the entire pixel portion 11 is uniformly irradiated withthe light L, and thus brightness of the pixel portion 11 is improved,and uniformity of the brightness is increased.

In the present embodiment, as illustrated in FIG. 7, the air layer G isprovided between the light source device 40 and the light incidentsurface SE of the display panel 1. The light L emitted from the lightsource device 40 enters the light incident surface SE of the displaypanel 1 through the air layer G. The light L is refracted at the lightincident surface SE, and enters the outer surface 20A of the secondsubstrate 20 at a shallow angle. Therefore, the light L is less likelyto leak outside the display panel 1 from the outer surface 20A. Forexample, as illustrated in FIG. 8, in a case where the light sourcedevice 40 and the light incident surface SE are in contact with eachother, the light L emitted from the light source device 40 enters theouter surface 20A without being refracted at the light incident surfaceSE. Therefore, the angle to enter the outer surface 20A becomes large.Therefore, the light L may leak outside the display panel 1 withoutbeing totally reflected at the outer surface 20A. In the presentembodiment, the amount of the light L leaking outside the display panel1 is small, and thus a bright image can be obtained.

Second Embodiment

FIG. 9 is a sectional view of a display device 200 according to a secondembodiment. In the present embodiment, a configuration element common tothe first embodiment is denoted with the same reference sign, anddetailed description is omitted.

A different point in the present embodiment from the first embodiment isthat a semiconductor element 50 is mounted on an FPC 60. A displaymethod in a display panel 1 is the same as that of the first embodiment.That is, as illustrated in FIG. 5, a liquid crystal layer 30 is in anon-scattering state in which light L is not scattered when no voltageis applied between pixel electrodes 13 and a common electrode 14. Thelight L is propagated in a direction away from a light source device 40while reflected between a first substrate 10 and a second substrate 20.As illustrated in FIG. 6, the liquid crystal layer 30 is in a scatteringstate in which the light L is scattered when a voltage is appliedbetween the pixel electrodes 13 and the common electrode 14. The light Lis propagated while being reflected between the first substrate 10 andthe second substrate 20, and is scattered in a pixel PX in a scatteredstate. The scattered light L is radiated to an outside the display panel1, and is observed as image light.

According to this configuration, the light L from the light sourcedevice 40 can be suppressed from entering a semiconductor element 50.Therefore, the light source device 40 can be arranged in the terminalportion 12 while suppressing malfunction of the semiconductor element50. Further, in the present embodiment, the semiconductor element 50 ismounted on the FPC 60, and thus a distance between the semiconductorelement 50 and the light source device 40 is large. Therefore, thesemiconductor element 50 is less likely to be deteriorated by heat fromthe light source device 40.

Further, the FPC 60 is formed of polyimide or the like, and opticaltransmittance of the FPC 60 is smaller than optical transmittance of thefirst substrate 10. Therefore, a part of the light L reflected at anouter surface 10A of the first substrate 10 and going toward thesemiconductor element 50 is shielded by the FPC 60. Therefore,malfunction of the semiconductor element 50 is suppressed.

Third Embodiment

FIG. 10 is a plan view of a display device 300 according to a thirdembodiment. In the present embodiment, a configuration element common tothe first embodiment is denoted with the same reference sign, anddetailed description is omitted.

A different point in the present embodiment from the first embodiment isthat light source devices 40 are provided only to a terminal portion 12.No light source devices 40 are provided outside a first substrate 10.

In the present embodiment, for example, as a plurality of the lightsource devices 40, a first light source device 41 and a third lightsource device 43 are provided. First light L1 radiated from the firstlight source device 41 travels from a first side 11 a toward a secondside 11 b. Third light L3 radiated from the third light source device 43travels from a third side 11 c to a fourth side 11 d.

First semiconductor elements 51 are not provided in directions intowhich the first light L1 and the third light L3 are propagated. Secondsemiconductor elements 52 are not provided in directions into which thefirst light L1 and the third light L3 are propagated. Therefore,occurrence of malfunction in the first semiconductor elements 51 and thesecond semiconductor elements 52 can be suppressed.

Further, in this configuration, all of the light source devices 40 areput together on the first substrate 10. Therefore, a display panel 1 andthe light source devices 40 can be integrally treated, and conveyanceand assembly work become easy. Further, all of the light source devices40 are fixed in a state where the light source devices 40 are positionedto the second substrate 20. Therefore, in a case where the displaydevice 300 is accommodated in a case, it is not necessary to provide amechanism to position the light source devices 40 in the case.Therefore, the structure of the case can be simplified.

Fourth Embodiment

FIG. 11 is a sectional view of a display device 400 according to afourth embodiment. In the present embodiment, a configuration elementcommon to the first embodiment is denoted with the same reference sign,and detailed description is omitted.

A different point in the present embodiment from the first embodiment isthat light source devices 40 not arranged in a terminal portion 12 havea height comparable to the thickness of a display panel 1. For example,a second light source device 42 and a fourth light source device 44 havea height comparable to the thickness of the display panel 1.

The second light source device 42 and the fourth light source device 44are arranged to face both of a first substrate 10 and a second substrate20. The second light source device 42 and the fourth light source device44 allow light L to enter both of an end surface of the first substrate10 and an end surface of the second substrate 20 at the same time.Therefore, an amount of the light L entering the display panel 1 becomeslarge, and a bright image can be obtained.

Fifth Embodiment

FIG. 12 is a sectional view of a display device 500 according to a fifthembodiment. In the present embodiment, a configuration element common tothe second embodiment is denoted with the same reference sign, anddetailed description is omitted.

A different point in the present embodiment from the second embodimentis that light source devices 40 not arranged in a terminal portion 12have a height comparable to the thickness of a display panel 1. Forexample, a second light source device 42 and a fourth light sourcedevice 44 have a height comparable to the thickness of the display panel1.

The second light source device 42 and the fourth light source device 44are arranged to face both of a first substrate 10 and a second substrate20. The second light source device 42 and the fourth light source device44 allow light L to enter an end surface of the first substrate 10 andan end surface of the second substrate 20 at the same time. Therefore,an amount of the light L entering the display panel 1 becomes large, anda bright image can be obtained.

Sixth Embodiment

FIG. 13 is a sectional view illustrating a variation of arrangement of alight source device 40.

In the first embodiment, the air layer G is provided between the lightsource device 40 and the light incident surface SE of the display panel1 to suppress leakage of the light L, which has entered the lightincident surface SE, by directly passing through the display panel 1. Inthe present embodiment, a reflecting layer 70 is provided in a positionwhere leakage of light occurs, in place of providing an air layer Gbetween a light source device 40 and a light incident surface SE. Arange to provide the reflecting layer 70 is determined according to arefractive index of a second substrate 20 and a flare angle of light L.The reflecting layer 70 is provided in a range in which the light Lenters an outer surface 20A at an angle smaller than a critical angle.

According to this configuration, a distance between the light incidentsurface SE and the light source device 40 becomes short, and thus aterminal portion 12 can be made small. Therefore, downsizing of adisplay device can be achieved while suppressing leakage of the lightfrom the display panel 1.

Seventh Embodiment

FIG. 14 is a plan view of a display device 600 according to a seventhembodiment. In the present embodiment, a configuration element common tothe first embodiment is denoted with the same reference sign, anddetailed description is omitted.

A different point in the present embodiment from the first embodiment isthat a terminal portion 12 is provided only to one side of a firstsubstrate 10. A thin film transistor of a pixel portion 11 is a thinfilm transistor using polycrystal silicon, for example, low temperaturepoly-silicon (LTPS). A semiconductor element 50 is electrically coupledwith gate lines and data lines pulled out from the pixel portion 11. Thesemiconductor element 50 is mounted on an FPC 60. The light sourcedevice 40 is arranged between the pixel portion 11 and the semiconductorelement 50, and irradiates the pixel portion 11 with light L.

According to this configuration, the light L from the light sourcedevice 40 does not directly enter the semiconductor element 50.Therefore, malfunction of the semiconductor element 50 is suppressed.

Eighth Embodiment

FIG. 15 is a plan view of a display device 700 according to an eighthembodiment. In the present embodiment, a configuration element common tothe seventh embodiment is denoted with the same reference sign, anddetailed description is omitted.

In the present embodiment, a plurality of light source devices 40 areprovided around a pixel portion 11. For example, as the plurality oflight source devices 40, a first light source device 41 and a secondlight source device 42 are provided. The first light source device 41 isarranged between the pixel portion 11 and a semiconductor element 50.The second light source device 42 is arranged in a position facing thefirst light source device 41 across the pixel portion 11.

The first light source device 41 irradiates the pixel portion 11 withfirst light L1. The first light L1 does not directly enter thesemiconductor element 50, and thus malfunction of the semiconductorelement 50 by the first light L1 is suppressed. Second light L2 radiatedfrom the second light source device 42 is propagated toward thesemiconductor element 50 and is attenuated in the process ofpropagation, and thus malfunction is less likely to occur in thesemiconductor element 50. Therefore, the pixel portion 11 can beilluminated by the plurality of light source devices 40 whilesuppressing malfunction of the semiconductor element 50.

Ninth Embodiment

FIG. 16 is a sectional view of a display device 800 according to a ninthembodiment. FIG. 17 is a sectional view illustrating a configuration ofa light source 46. In the present embodiment, a configuration elementcommon to the first embodiment is denoted with the same reference sign,and detailed description is omitted.

As illustrated in FIG. 17, the light source 46 includes a luminous body75, a fluorescent body 76, and a reflector 77. The reflector 77 includesa recess 77 a that accommodates the luminous body 75 and the fluorescentbody 76. The luminous body 75 is fixed to a bottom surface of the recess77 a. The luminous body 75 is covered with the fluorescent body 76. Thefluorescent body 76 absorbs a part of light radiated from the luminousbody 75, and emits light having a different wavelength from a wavelengthof the radiated light of the luminous body 75. The luminous body 75emits, for example, blue light. The fluorescent body 76 converts theblue light into yellow light, for example. Accordingly, white light L isradiated from the light source device 40. A surface of the fluorescentbody 76 exposed in the recess 77 a is a light irradiation surface 40 a.

As illustrated in FIG. 16, a first semiconductor element 51(50) isarranged in a position where shadow of second light L2 is formed by thefirst light source device 41, for example. The second light L2propagated inside the display panel 1 and emitted from a first endsurface 1 a is shielded by the first light source device 41. The secondlight L2 having entered the first light source device 41 is reflected bya reflector 77, and does not enter a first semiconductor element 51.Therefore, malfunction of the first semiconductor element 51 issuppressed. Although illustration is omitted, a second semiconductorelement 52 is arranged in a position where shadow of fourth light L4 isformed by a fourth light source device 44. Therefore, the fourth lightL4 is suppressed from entering the second semiconductor element 52.

Note that the present embodiment is applied to the first to eighthembodiments.

Favorable embodiments of the present invention have been described.However, the present invention is not limited to these embodiments. Thecontent disclosed in the embodiments is merely examples, variousmodifications can be made without departing from the points of thepresent invention. Appropriate modifications made without departing fromthe points of the present invention obviously belong to the technicalscope of the present invention. All of inventions that would beappropriately designed and modified, and implemented by a person skilledin the art on the basis of the above-described invention also belong tothe technical scope of the present invention as long as the inventionsinclude the gist of the present invention.

For example, in the above-described embodiment, the terminal portion 12is provided in the L-shaped manner along the two sides of the pixelportion 11. However, the shape of the terminal portion 12 is not limitedthereto. The terminal portion 12 may be provided along one side, orthree or more sides of the pixel portion 11. Further, the number of thelight source devices 40 is not limited to four or two, and may be one orthree. Further, the types and numbers of the semiconductor element 50are not limited to those described in the above-described embodiments.

The present invention can be widely applied to a display deviceaccording to the following aspects.

(1) A display device comprising:

a first substrate including a pixel portion and a terminal portion;

a second substrate arranged to face the pixel portion;

a first light source device arranged in the terminal portion, andirradiating a first end surface of the second substrate with firstlight;

a liquid crystal layer arranged between the first substrate and thesecond substrate; and

a semiconductor element arranged on a side opposite to a side of thepixel portion across the first light source device, and electricallycoupled with the terminal portion, wherein

the first light is propagated while reflected between the firstsubstrate and the second substrate, and

the liquid crystal layer modulates the propagated first light.

(2) The display device according to (1), comprising:

a second light source device arranged in a position facing the firstlight source device with the pixel portion between the first and secondlight source devices, and irradiates a second end surface of the secondsubstrate with second light.

(3) The display device according to (1) or (2), wherein

the semiconductor element is mounted in the terminal portion.

(4) The display device according to (3), wherein

a resin is provided between the semiconductor element and the firstlight source device.

(5) The display device according to (1) or (2), comprising:

a flexible printed circuit substrate electrically coupled with theterminal portion, wherein

the semiconductor element is mounted on the flexible printed circuitsubstrate.

(6) The display device according to (5), wherein

optical transmittance of the flexible printed circuit substrate issmaller than optical transmittance of the first substrate.

What is claimed is:
 1. A display device comprising: a first substrateincluding a pixel portion and a terminal portion; a second substratearranged to face the pixel portion, the second substrate having a firstend surface and a second end surface; a first light source devicearranged in the terminal portion, the first light source deviceirradiating the first end surface with first light; a second lightsource device arranged in a position facing the first light sourcedevice, the second light source device irradiating the second endsurface with second light, and the pixel portion being arranged betweenthe first light source device and the second light source device, aliquid crystal layer arranged between the first substrate and the secondsubstrate, the liquid crystal layer including polymer and fine liquidcrystal particles dispersed in the polymer; and a semiconductor elementarranged on a side opposite to a side of the pixel portion across thefirst light source device, the semiconductor element being electricallycoupled with the terminal portion, wherein: the first light from thefirst light source device is propagated from the first end surface tothe second end surface, and the second light from the second lightsource device is propagated from the second end surface to the first endsurface, while the first light and the second light being reflectedbetween the first substrate and the second substrate via the liquidlayer interposed therebetween; the first light source device is disposedbetween the semiconductor element and the second light source devicefrom which the second light reaches the first end surface, the liquidcrystal layer, which includes the polymer and the fine liquid crystalparticles, modulates the propagated first light from the first lightsource and the propagated second light from the second light sourcedevice; and the polymer and the fine particles have optical anisotropy.2. The display device according to claim 1, wherein the semiconductorelement is mounted in the terminal portion.
 3. The display deviceaccording to claim 2, wherein the first light source device is disposedbetween the second light source device and the semiconductor elementthat has a first-light side surface facing the first light sourcedevice, the first-light side surface being coated with a resin having alow thermal conductivity.
 4. The display device according to claim 1,comprising: a flexible printed circuit substrate electrically coupledwith the terminal portion, wherein the semiconductor element is mountedon the flexible printed circuit substrate.
 5. The display deviceaccording to claim 4, wherein optical transmittance of the flexibleprinted circuit substrate is smaller than optical transmittance of thefirst substrate.
 6. The display device according to claim 1, wherein thefirst light source device is disposed between the semiconductor elementand the first end surface of the second substrate, an air layer isprovided between the first light source device and the first end surfaceof the second substrate, such that the light emitted from the firstlight source device and entering the first end surface through the airlayer is refracted at the first end surface and enters an outer surfaceof the second substrate at a shallow angle, allowing to reduce the lightto leak outside from the outer surface of the second substrate.
 7. Thedisplay device according to claim 1, wherein the semiconductor elementcomprises a plurality of semiconductor elements each having afirst-light side surface that faces the first light source device, andthe first light source device is disposed between the semiconductorelements and the second light device such that a side surface of thefirst light source device overlaps all of the first-light side surfacesof the first semiconductor elements in a direction in which the firstlight source device and the second light source device oppose eachother.
 8. A display device comprising: a first substrate including apixel portion and a terminal portion; a second substrate arranged toface the pixel portion, the second substrate having a first end surface,a second end surface facing the first end surface, a third end surface,and a fourth end surface facing the third end surface; a first lightsource device arranged in the terminal portion, the first light sourcedevice irradiating the first end surface with first light; a secondlight source device arranged in a position facing the first light sourcedevice, the second light source device irradiating the second endsurface with second light, and the pixel portion being disposed betweenthe first light source device and the second light source device; athird light source device arranged in the terminal portion adjacent tothe third end surface, the third light source device irradiating thethird end surface with third light; a fourth light source devicearranged in a position facing the third light source device, the pixelportion being disposed between the third light source device and fourthlight source device, and the fourth light source device irradiating thefourth end surface with fourth light; a liquid crystal layer arrangedbetween the first substrate and the second substrate, the liquid crystallayer including polymer and fine liquid crystal particles dispersed inthe polymer; and a semiconductor element arranged on a side opposite toa side of the pixel portion across the first light source device, thesemiconductor element being electrically coupled with the terminalportion; wherein: the first light from the first light source device ispropagated from the first side surface to the second side surface, thesecond light from the second light source device is propagated from thesecond end surface to the first end surface, the third light from thethird light source device is propagated from the third end surface tothe fourth end surface, and the fourth light from the fourth lightsource device is propagated from the fourth end surface to the third endsurface, while the first light, the second light, the third light, andthe fourth light being reflected between the first substrate and thesecond substrate via the liquid layer interposed therebetween; and theliquid crystal layer, which includes the polymer and the fine liquidcrystal particles, modulates the propagated first light from the firstlight source device, the propagated second light from the second lightsource device, the propagated third light from the third light sourcedevice, and the propagated fourth light from the fourth light sourcedevice.
 9. The display device according to claim 8, wherein the polymerand the fine particles have optical anisotropy.
 10. The display deviceaccording to claim 8, wherein the semiconductor element is mounted inthe terminal portion.
 11. The display device according to claim 10,wherein the semiconductor element comprises a plurality of thesemiconductor elements including a first semiconductor element and asecond semiconductor element, the first light source device is disposedbetween the second light source device and the first semiconductorelement that has a first-light side surface facing the first lightsource device, the first-light side surface being coated with a resinhaving a low thermal conductivity, the third light source device isdisposed between the fourth light source device and the secondsemiconductor element that has a third-light side surface facing thethird light source device, the third-light side surface being coatedwith the resin having the low thermal conductivity.
 12. The displaydevice according to claim 8, wherein the semiconductor element comprisesa plurality of the semiconductor elements including a firstsemiconductor element and a second semiconductor element, the firstlight source device is disposed between the first semiconductor elementand the first end surface of the second substrate, a first air layer isprovided between the first light source device and the first end surfaceof the second substrate, such that the light emitted from the firstlight source device and entering the first end surface through the airlayer is refracted at the first end surface and enters an outer surfaceof the second substrate at a shallow angle, allowing to reduce the lightto leak outside from the outer surface of the second substrate, a secondair layer is provided between the second light source device and thesecond end surface of the second substrate, such that the light emittedfrom the second light source device and entering the second end surfacethrough the air layer is refracted at the second end surface and entersan outer surface of the second substrate at a shallow angle, allowing toreduce the light to leak outside from the outer surface of the secondsubstrate, the third light source device is disposed between the secondsemiconductor element and the third end surface of the second substrate,a third air layer is provided between the third light source device andthe third end surface of the second substrate, such that the lightemitted from the third light source device and entering the third endsurface through the air layer is refracted at the third end surface andenters an outer surface of the second substrate at a shallow angle,allowing to reduce the light to leak outside from the outer surface ofthe second substrate, a fourth air layer is provided between the fourthlight source device and the fourth end surface of the second substrate,such that the light emitted from the fourth light source device andentering the fourth end surface through the air layer is refracted atthe fourth end surface and enters an outer surface of the secondsubstrate at a shallow angle, allowing to reduce the light to leakoutside from the outer surface of the second substrate.
 13. The displaydevice according to claim 8, wherein the semiconductor element comprisesa plurality of semiconductor elements, including: a first semiconductorelement having a first-light side surface that faces the first lightsource device and arranged on the side opposite to the side of the pixelportion across the first light source device; and a second semiconductorelement having a third-light side surface that faces the third lightsource device and arranged on a side opposite to a side of the pixelportion across the third light source device; the first light sourcedevice is disposed between the semiconductor elements and the secondlight device such that a side surface of the first light source deviceoverlaps all of the first-light side surfaces of the first semiconductorelements in a direction in which the first light source device and thesecond light source device oppose each other, and the third light sourcedevice is disposed between the second semiconductor elements and thefourth light device such that a side surface of the third light sourcedevice overlaps all of the third-light side surfaces of the secondsemiconductor elements in a direction in which the third light sourcedevice and the fourth light source device oppose each other.